Asda is facing continuing problems with unions at its distribution centres across the UK.

The supermarket group and the GMB union have been negotiating over working conditions and union recognition for a number of months but after talks collapsed, the GMB called for a strike ballot which closes on 21 June.

However, reports suggest that the GMB is now considering taking legal action against Asda, claiming that it is trying to persuade staff not to strike and could be planning to hire agency workers if industrial action went ahead, which would fall foul of employment laws.

A spokesman for Asda said that the company would not break any laws. He added: “It's a bit premature for the GMB to accuse us of breaking the law on this when the ballot's still taking place and we don't yet even know whether there will be any industrial action.”

Earlier this week Asda was accused of putting food hygiene at risk to cut costs, with the GMB union claiming that the number of staff at warehouses who monitor the dates and rotation of stock had been cut.